How galaxies form and evolve is one of the primary outstanding problems in extragalactic astronomy. I conduct a quantitative census of the relative importance of the major structural components (flattened and dynamically cold disk-dominated components versus puffy and dynamically hot spheroidal or triaxial bulges/ellipticals) in massive galaxies over cosmic time and across different environments in order to explore how galaxies evolve under the action of the various assembly mechanisms (major mergers, minor mergers, gas accretion, and internal secular processes) in these different regimes. I perform three inter-related analyses focusing on massive galaxies from z ~ 0 - 3 in both field and rich cluster environments. Important strengths of this thesis include the use of high-resolution, panchromatic imaging from some of the largest and deepest galaxy surveys with the Hubble Space Telescope (HST), Spitzer, and Chandra space telescopes, and also the inclusion of detailed comparisons between the empirical data and hierarchical ΛCDM-based models of galaxy evolution. / text

White dwarf stars are the burnt out remnants that remain after a star like the Sun has completed its nuclear evolution. In such a star there are no remaining nuclear energy sources, so the star evolves by simply radiating its stored thermal energy out into space. This may seem rather uninteresting, but in fact there is a wealth of physical phenomena that occur during this part of a star's life - from getting kicked at birth, to neutrino emission in early life, to some interesting high density physics, through to functioning as precise clocks that can provide an age for some of the oldest know stars in the Universe. Some of these phases will be illustrated with detailed observations taken recently with the Hubble Space Telescope.

Apresentamos fotometria profunda (V ~ 25,5) nas bandas V e I obtidas com a Wide Field and Planetary Camera 2 a bordo do telesc opio espacial Hubble para 7 campos distantes ~5º do centro da Grande Nuvem de Magalhães. Ajustamos isócronas aos diagramas cor-magnitude a fim de identficar diferentes populaões estelares nestes campos. Uma população velha (τ > 10¹º anos) foi encontrada em todos os campos. Alguns eventos de elevada formação estelar, com idades entre 2 x 109 e 4 x 109 anos, foram também encontrados em alguns campos localizados na região N/NO. Funções de luminosidade de estrelas de baixa massa (m ≤ 1; 1msol) foram obtidas para todos os campos. Aparentemente não há diferenças na mistura de populações entre os campos como sugerido através do teste Kolmogorov-Smirnov aplicados as funções de luminosidade. Finalmente, derivamos perfis de densidade para estrelas velhas e de idade intermediária. O primeiro apresenta uma inclinação levemente maior quando comparado com o último.

Apresentamos fotometria profunda (V ~ 25,5) nas bandas V e I obtidas com a Wide Field and Planetary Camera 2 a bordo do telesc opio espacial Hubble para 7 campos distantes ~5º do centro da Grande Nuvem de Magalhães. Ajustamos isócronas aos diagramas cor-magnitude a fim de identficar diferentes populaões estelares nestes campos. Uma população velha (τ > 10¹º anos) foi encontrada em todos os campos. Alguns eventos de elevada formação estelar, com idades entre 2 x 109 e 4 x 109 anos, foram também encontrados em alguns campos localizados na região N/NO. Funções de luminosidade de estrelas de baixa massa (m ≤ 1; 1msol) foram obtidas para todos os campos. Aparentemente não há diferenças na mistura de populações entre os campos como sugerido através do teste Kolmogorov-Smirnov aplicados as funções de luminosidade. Finalmente, derivamos perfis de densidade para estrelas velhas e de idade intermediária. O primeiro apresenta uma inclinação levemente maior quando comparado com o último.

The structure of the plasma in Jupiter’s vast magnetosphereis complicated and not fully understood. One way to study the plasma is to look at auroral emissions from the moonIo as it moves through different regions of the plasma torus that surrounds Jupiter. In this paper, the correlation between aurorabrightness on Io and the plasma density at the position of the moon is investigated. If a correlation exists, auroral emissonson Io could be used as a diagnostic for the current state ofJupiter’s plasma environment. For this purpose, a model of the Io plasma torus is developed, combining ideas from different existing models. The model is compared with observations of aurorae on Io made by the Hubble Space Telescope. Io’s position at the time of the observations is obtained with SPICE, a software developed by NASA. A moderate correlation is found when using the whole data set of observations. However, a strong correlation is found for observations on the dusk side of Jupiter. Strong correlations are also found when studying individual years and epochs. / Strukturen på plasman i Jupiters vidsträckta magnetosfär är komplicerad och inte fullständigt känd. Ett sätt att studera plasman är att undersöka ljuset från polarsken på månen Io då den passerar genom olika regioner av det torusformade plasmamolnet som omsluter Jupiter. I denna artikel undersöks korrelationen mellan polarskenets ljusstyrka och plasmans densitiet kring månens position. Om ett sådant samband finns skulle ljusstyrkan hos månens polarsken kunna användas som diagnostik för plasmans aktuella tillstånd. För detta ändamål utvecklas en modell av plasmatorusen genom att kombinera ide´er från flera tidigare modeller. Modellen jämförs sedan med observationer av polarskenet på Io genomförda med rymdteleskopet Hubble. Månens position vid de olika tidpunkterna bestäms med hjälp av SPICE, en mjukvara utvecklad av NASA. En måttligt stark korrelation uppnås när hela datamängden används. När däremot endast data från Jupiters gryningssida används uppnås en korrelation. Det hittas även starka samband när enskilda år studeras. / Kandidatexjobb i elektroteknik 2022, KTH, Stockholm

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Several studies have been conducted with the aimof finding water plumes at Jupiter’s moon Europa. The possibleevidence of plumes is important for two future space missions,the JUpiter ICy moons Explorer (JUICE) and the Europa clippermission. Multiple observations of Europa in transit of Jupiterhave been obtained with the Hubble Space Telescope (HST).In an analysis by Sparks et al. 2016 three plume candidateswere found. Later on, in the report Sparks et al. 2017 anadditional candidate was found at a similar location as a previouscandidate, potentially making the evidence of plume existencestronger. In 2020 Giono et al. reproduced the results from Sparkset al. 2016 and found uncertainties in the method that hadbeen used when finding these plume candidates. First Giono etal. claim that the position of Europa in the observation wasinadequately determined. Also, positive outliers had not beenconsidered when analyzing the z-statistic. In this study, thealgorithm developed by Giono et al. has been used to reproducethe results from Sparks et al. 2017 where additional evidence forplume activity was presented. The algorithm was then applied tothe previous observation, where plume activity had been foundin the same location. Lastly, the two observations were mergedinto one image and the algorithm was applied once again. Theresults of the z-statistic from the observations gave large negativeoutliers which can be considered as plumes. However, positive andnegative outliers had similar significance for the two independentobservations which somewhat diminishes the evidence. Also,misalignment between model and observation generates distortedstatistics. The statistical uncertainties and fluctuations can easilybe mistaken as evidence of plume existence. / Flera studier har utförts med syftet attupptäcka vattenplymer på Jupiters måne Europa. Det eventuellabeviset för att plymer existerar är viktigt för två framtidarymduppdrag, JUpiter ICy moons Explorer (JUICE) och Europaclipper mission. Flera observationer av när Europa passerarframför Jupiter har erhållits av Hubbleteleskopet (HST). I enanalys av Sparks et al. 2016 har tre kandidater för plymerhittats. I rapporten av Sparks et al. 2017 hittades ytterligare enkandidat på ungefär samma ställe, vilket potentiellt kunde stärkabeviset för att det var plymer. År 2020 reproducerade Giono et alresultaten från Sparks et al. 2016 och hittade brister i metodennär dessa plymkandidater hittades. Först pöangterar de att Europas position i observationen var felaktig. Dessutom togs detinte hänsyn till positiva avvikelser när z-statistiken betraktades.I den här rapporten har algoritmen som skapades av Gionoet al. använts för att reproducera resultaten från Sparks et al.2017 där ytterligare bevis för plymer presenterades. Algoritmenapplicerades sedan på den föregående observationen där bevis förplymer hade hittats i samma område. Därefter slogs dessa bilderihop och analyserades som en bild. Resultatet av z-statistikenfrån observationerna gav stora negativa avvikelser vilket kanses som en plym av vattenånga. Dock eftersom positiva ochnegativa avvikelser hade liknande signifikans för de två enskildaobservationerna försvagas beviset för att plymer skulle existera.Dessutom genererar lokala fel mellan modell och observation enförvrängd statistik där statistiska osäkerheter och fluktuationerenkelt kan misstas som bevis för att vattenplymer existerar / Kandidatexjobb i elektroteknik 2021, KTH, Stockholm

International Telemetering Conference Proceedings / October 25-28, 1993 / Riviera Hotel and Convention Center, Las Vegas, Nevada / The Hubble Space Telescope (HST) Observatory Management System (HSTOMS), located at the Goddard Space Flight Center (GSFC), provides telemetry, command, analysis and mission planning functions in support of the HST spacecraft. The Telemetry and Command System (TAC) is an aging system that performs National Aeronautics and Space Administration (NASA) Communications (Nascom) block and telemetry processing functions. Future maintainability is of concern because of the criticality of this system element. HSTOMS has embarked on replacing the TAC by using functional elements developed by the Microelectronics Systems Branch of the GSFC. This project, known as the Transportable TAC (TTAC) because of its inherent flexibility, is addressing challenges that have resulted from applying recent technological advances into an existing operational environment. Besides presenting a brief overview of the original TAC and the new TTAC, this paper also describes the challenges faced and the approach to overcoming them.

Foram analisados espectros óticos de fenda longa de 29 galáxias que hospedam núcleos ativos (AGNs), sendo 6 galáxias Seyfert 1, 18 galáxias Seyfert 2, 4 Rádio-galáxias de linhas estreitas (NLRG) e 1 Rádio-galáxia de linhas largas (BLRG). Estas galáxias apresentam emissão por gás de alta excitação que se estende em alguns casos a 10 kpc do núcleo. O objetivo do presente trabalho consiste em estudar e caracterizar as propriedades físicas da região estendida de linhas estreitas (ENLR) destes objetos bem como propriedades da fonte central. A distribuição radial de parâmetros que caracterizam o gás emissor em cada galáxia, tais como brilho superficial das linhas de emissão, densidade do gás, massa, extinção e excitação são obtidos. Estes valores característicos são comparados entre as diferentes classes de atividade nuclear presentes em nossa amostra, bem como às propriedades de galáxias normais com o mesmo tipo de Hubble quando possível. Nós encontramos que a massa de gás ionizado é consistente com a hipótese de que o gás é “originado” na fotoionização pela fonte central das nuvens de HI préexistentes na galáxia hospedeira. Os valores observados das razões entre as linhas estreitas de emissão são comparados com os obtidos através de modelos de fotoionização gerados com o código MAPPINGS Ic, obtendo os parâmetros do modelo – densidade, índice espectral da distribuição de energia e da metalicidade do gás – que melhor reproduzem as observações. Observamos que a variação da abundância química do gás é necessária para explicar o espalhamento nos valores observados. Adicionalmente, comparamos os valores observados com os obtidos com modelos de choques gerados por Dopita & Sutherland. Investigamos também a influência da emissão proveniente de regiões HII ao espectro observado – a qual concluímos ser importante particularmente nas regiões emissoras mais distantes do que 2 kpc do núcleo. Nós determinamos a luminosidade ionizante da fonte central nos AGNs usando a aproximação de que as nuvens de gás são limitadas por radiação, e obtivemos os correspondentes valores para o fator de cobertura do gás. Esta luminosidade ionizante foi então comparada com a luminosidade observada em raios-X na banda 2 –10 keV, através de aproximações para a distribuição espectral de energia (SED). Para 9 galáxias Seyfert 2 a luminosidade observada está disponível, e verificamos que nosso método recupera a luminosidade do AGN em raios-X – assim como obtida dos dados do satélite ASCA – bem como identifica os 3 casos Compton espessos. Por fim, investigamos a natureza do contínuo infravermelho (IR) médio e distante – comparandose a luminosidade observada no IR, calculada a partir dos fluxos IRAS, com a luminosidade predita para um toro que envolve a fonte central absorvendo a radiação incidente e re-emitindo esta no infravermelho. Encontramos que a luminosidade observada no IR é consistente com a luminosidade predita para o torus.

Les études détaillées d'amas de galaxies confirmés à grands redshifts sont peu nombreuses. L’objectif de cette Thèse est d’établir le premier catalogue d'amas confirmés spectroscopiquement à grand redshift et, pour la première fois à ces redshifts, d’étudier de manière statistique les propriétés des galaxies membres des amas. Dans cette Thèse, nous caractérisons et étudions 20 candidats amas à redshifts 1.4 < z < 2.8 parmi les candidats les plus prometteurs de l’échantillon CARLA. Nous réduisons et analysons des données spectroscopiques grism sans fente et imagerie proche-infrarouge des amas candidats, obtenues avec le télescope spatial Hubble. Nous mesurons plus de 700 redshifts au sein des champs observés, et confirmons spectroscopiquement 16 amas CARLA dans l’intervalle 1.4 < z < 2.8; ces amas sont associés à des noyaux galactiques actifs à fortes émissions radios (RLAGN) en leur centre, par sélection. Cet effort fait plus que doubler le nombre d’amas confirmés à ces redshifts. Nous étudions également le taux de formation stellaire des galaxies membres des amas en fonction de leur masses stellaires, et de la distance aux RLAGN. Nous trouvons que les galaxies membres massives sont situées sous la séquence principale jusqu’à z=2, ce qui suggère déjà à ces redshifts une évolution accélérée des galaxies massives au sein des amas. Nous trouvons également une concentration plus importante de membres actifs à plus petits rayons des RLAGN, jusqu’à z=2. Ceci est en accord avec un renversement de la relation densité vs. taux de formation stellaire pour nos amas CARLA à 1.4 < z < 2.0, ce qui suggère que les amas CARLA représentent une phase de transition de l’évolution des galaxies au sein des amas. Nous étudions également les populations stellaires de deux de nos amas confirmés à redshift z=2.0. Nous analysons les relations couleurs-couleurs et couleurs-magnitudes de ces deux amas et montrons que l’une des structures à z=2 possède une séquence rouge de galaxies passives. Globalement, nos résultats démontrent que les amas CARLA représentent des structures riches comprenant des populations mixtes de galaxies évoluées et massives sans formation stellaire, et des galaxies actives formant des étoiles. Cet échantillon sans précédent de 16 amas confirmés spectroscopiquement dans l’intervalle de redshift 1.4 < z < 2.8 constitue un échantillon idéal pour étudier statistiquement la phase de transition des amas de galaxies, ainsi que les mécanismes de suppression de la formation stellaire. (Abrégé) / Detailed studies of high-redshift confirmed galaxy clusters are based on a few individual objects. In this Thesis, we therefore aim at building the first sample of spectroscopically confirmed clusters at high-redshifts and, for the first time at these redshifts, statistically infer cluster member galaxy properties. In this Thesis, we study and characterize 20 cluster candidates at redshifts 1.4 < z < 2.8, which represent the most promising cluster candidates from the CARLA sample. We reduce and analyze slitless grism spectroscopic and near-infrared imaging data of the fields, obtained with the Hubble Space Telescope. We measure redshifts for over 700 star-forming sources in the 20 fields, and we spectroscopically confirm 16 CARLA clusters in the range 1.4 < z < 2.8; by selection, these clusters are associated with powerful radio-loud active galactic nuclei (RLAGN) at their center. This effort alone more than doubles the number of confirmed clusters at these redshifts. We study cluster member star-formation rates (SFRs) as a function of their stellar masses and distances from the RLAGN. We find that massive members are located below their star-forming main-sequence up to z=2. This implies that the massive star-forming end of the cluster population already followed an accelerated evolution at these high redshifts. We also find an increasing concentration of star-forming members with smaller radii relative to the RLAGN, at all redshifts up to z=2. Our 1.4 < z < 2.0 cluster members are therefore consistent with a reversal of the SFR-density relation. This is a first evidence showing that CARLA clusters represent a transition phase for cluster galaxy evolution. We also study stellar populations of two of our confirmed CARLA clusters at z=2.0. We study their color-color and color-magnitude relations and show that one of the two structures is comprised of a z=2 red sequence of passive candidate members. Together, these results provide clear evidence that our confirmed CARLA clusters represent rich structures comprised of mixed populations, including both evolved, passive, massive galaxies, and galaxies with ongoing star formation. Together, this unprecedented sample of 16 confirmed clusters at 1.4 < z < 2.8 constitutes an ideal sample for further statistical investigation of the cluster transition phase, including study of quenching mechanisms. (Abridged)